This invention relates to a central dictation system, and in paritcular, to apparatus for providing and for utilizing an indication of the cumulative amount of dictated material awaiting transcription.
Central dictation systems are known wherein a central record/playback unit is adpated to be individually accessed by any one of a plurality of remote dictate stations so as to record dictated information on a record medium. In such systems, the central record/playback unit can be accessed by only a single dictate station at any given time. While one dictate station is in communication with the central unit all other dictate stations are excluded, or locked out, from also communicating with the central unit.
The advantage of such central dictation systems is that individual dictators need not be concerned with the manipulation of various recording media, not need they attend to the time consuming task of delivering recording media having dictation thereon to appropriate personnel for transcription. In the typical central dictation system, a recording medium having a relatively large capacity for recording dictation is provided so that received dictation communicated from a remote dictation station is recorded on the medium and can be subsequently reproduced for transcription. In one type of central record/playback unit, the record medium consists of an endless loop of magnetic tape which is driven past a dictation transducing station and is also driven past a transcribing transducing station. These stations are essentially operated independently of each other so that a dictation operation can be performed simultaneously with and independently of a transcribing operation. Thus, such a central dictation system advantageously permits the efficient use of dictating and transcribing apparatus. Moreover, dictated information can be almost immediately transcribed - an earlier portion of a dictated message being transcribed while dictation still is in progress. A typical prior art central dictation system having an endless loop of magnetic tape is described in U.S. Pat. No. 3,817,436 issued June 18, 1974, and is assigned to Dictaphone Corporation, the assignee of the present invention.
It is preferable, in many applications of a central dictation system, to provide an indication of the amount of dictated material which is awaiting transcription. For a system wherein the record medium is an endless loop of magnetic tape, an indication of the quantity of dictated tape which is awaiting transcription is also an indication of the quantity of tape which is available for further recording. Such indications can be used to evaluate a transcribing operator and/or a dictating operator. In addition, for a central dictation system wherein a plurality of record/playback units are provided, the indication of the quantity of dictated tape awaiting transcription can be used to determine which of the units are approaching their respective capacities and which of the units can be made available for further communication.
In conventional reel-to-reel dictation systems, the quantity of tape which is paid out from a supply reel to a take-up reel are provided in the form of an indexing device, such as a numerical count, or a sliding scale. However, this indication does not afford any representation of the amount of dictated tape which has been transcribed. Hence, the indication is not affected by a transcribing operation; and there is no representation as to the cumulative or net amount of dictated tape which remains for transcription. Also, in these prior art indexing devices, the indication of paid-out tape usually is derived from the reel-driving elements. Accordingly, such indications are produced in response to reel rotation, drive belt movement, gear movement, or the like. Although there usually is a correlation between the operation of such elements and the amount of tape paid-out from the supply reel, a more accurate indication of the quantity of tape so paid-out usually is desired.
It has been proposed that, in a central dictation system wherein an endless loop of magnetic tape is used to record dictated information at a dictation transducing station and from which the dictated information is transcribed at a transcribing transducing station, to provide a tape movement indicating system wherein the net accumulation of dictated tape is indicated. This proposed system requires the use of a differential stepping motor which is mechanically connected to an indicating pointer. As an example, the motor is driven to step up when a quantity of dictated tape issues from the dictation transducing station, and is driven to step down an equal amount when an equal quantity of dictated tape is transcribed.
Unfortunately, an attendant disadvantage of this proposed system is that the use of a differential motor requires a highly precise mechanical instrument which is costly to manufacture and which requires a strict maintenance schedule to maintain in proper working condition. Also, in the proposed system, the differential motor is subject to erroneous operation if a given quantity of dictated tape and the same quantity of transcribed tape are simultaneously moved. In that event, the differential motor might be simultaneously subjected to a step-up and a step-down operation, wherein the resultant effect cannot be predicted and often is erroneous. Accordingly, during prolonged dictate and transcribe operations, the operation of the differential motor can result in cumulative errors such that the indication of dictated tape remaining in the recording/playback unit does not correlate with the actual quantity of such tape.